Diabetic diarrhea is an uncommon complication of long-standing diabetes mellitus. Except when a diagnostic evaluation reveals a treatable underlying cause, the disorder is often refractory. Our study is a randomized, double-blind, placebo-controlled, cross-over design trial to investigate the therapeutic efficacy of transdermal clonidine and subcutaneous octreotide in 20 adult individuals with idiopathic diabetic diarrhea.